F152 (LL-Z1640-2), a zearalenone-like macrolide, was first isolated from shake flask fermentation, crude extracts of which inhibited the ciliated protozoan Tetrahymena pyriformis (see, McGahren et al. J. Org. Chem. 1978, 43, 2339). Although initial biological
studies using this natural product failed to yield any particularly interesting activities, the possibility of preparing additional derivatives and/or further exploring their biological activity was undertaken. For example, F152 and certain isomers thereof inhibit the phosphorylating enzyme Map/Erk kinase (MEK) and may be useful for the treatment of certain MEK-related cancers and other diseases characterized by the formation of neoangiogenesis (see, e.g., GB 323 845). Derivatives of F152 have also been shown to have activity as tyrosine kinase inhibitors, which are useful, for example, for the treatment of cancer and inflammatory disorders (see, e.g., EP 606 044; WO 00/38674; JP 8-40893; WO 96/13259; U.S. Pat. No. 5,728,726; U.S. Pat. No. 5,674,892; U.S. Pat. No. 5,795,910). Often, however, F152 and derivatives thereof are obtained by fermentation techniques and modifications to the natural product and thus were limited in the number and types of derivatives that could be prepared and evaluated for biological activity. Additionally, although F152 and certain derivatives thereof have demonstrated potent in vitro activities, these compounds may be biologically unstable (for example, they are susceptible to enone isomerization in mouse and human plasma), thereby limiting the development of these compounds as therapeutics for the treatment of humans or other animals.
Recently, F152 analogues have been shown to be inhibitors of NF-κB activation, and MEK1 (See, e.g., U.S. application Ser. No. 10/507,067 and U.S. Application Publication No.: US 2004/0224936). The compounds were also reported to inhibit AP-1 activation and some protein kinases (for example, MEKK, PDGFr, VEGFr). Based on these mechanisms of action, it was suggested that the compounds inhibit the production of various pro-inflammatory and/or immunologic cytokines such as TNFα, IL-1, IL-6, IL-8, IL-2 etc, and also inhibit the production of various pro-inflammatory molecules under the regulation of NF-κB pathway such as prostaglandins produced from COX-2, ICAM-1 and MMP-1 and 3 etc. Also, it was reported that the compounds have the ability to inhibit cell proliferation under the regulation of AP-1 pathway through the inhibition of MEK1. In addition, it was reported that the compounds have ability to inhibit angiogenesis, likely based on the inhibitory activity on VEGFr kinase and weak inhibitory activity on PDGFr kinase.